Darkness promotes flowering in the absolute long-day requiring plant, Lolium temulentum L. Ceres

Vegetative plants of the long-day grass Lolium temulentum L. Ceres were exposed to threshold long days or light breaks. Protracted darkness given just afterwards clearly promoted flowering and was weakly inductive on its own. The promotive effect of darkness was restricted to floral induction since further apical development was weak.